Sustainable ammonia synthesis from nitrate wastewater via graphdiyne Mo-Cu-C≡C interfaces.

Chen, Zhaoyang; Zhao, Shuya; Xiao, Qian; Tian, Yue; Lu, Xiaofeng; Xue, Yurui · Nat Commun · 2026

basic_science · Level V

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Abstract

Electrochemical green ammonia (NH<sub>3</sub>) production using renewable electricity is sustainable but suffers from selectivity-activity-stability trade-off under industrial conditions. Here we report an atomic interface engineering strategy enabling in-situ assembly and coupling of hexaethynylbenzenes on molybdenum-copper oxidesto form an sp-hybridized Mo/Cu-C≡C heterointerface. It features dual d-orbital hybridization (Mo 4d-C 2p and Cu 3d-C 2p) weakening N-O bond by 36.85% and lowering activation barrier by 0.43 eV, reversible electron-buffer facilitating proton-coupled electron transfer, and self-regulated charge compensation between metal atoms and -C≡C- atomic wires, collectively endowing high activity and near-complete hydrogen evolution reaction suppression. The resulting catalyst achieves high NH<sub>3</sub> yielding rate (Y<sub>NH3</sub>, 2.45 mmol h<sup>-1</sup> cm<sup>-2</sup>) and Faradaic efficiency (~100%) under ambient conditions. A prototype flow electrolyzer operating with this catalyst sustains industrial-current densities of 500 mA cm<sup>-2</sup> for 300 hours with <3% activity decay, yielding potable water from nitrate wastewater. The membrane electrode assembly (MEA) achieves 380 h stable operation at the same current density with Y<sub>NH3</sub> of 3.64 mmol h<sup>-1</sup> cm<sup>-2</sup>.